CVE-2025-23019
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIPv6-in-IPv4 tunneling (RFC 4213) allows an attacker to spoof and route traffic via an exposed network interface.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis vulnerability involves IPv6-in-IPv4 tunneling (RFC 4213) where an attacker can spoof and route traffic through an exposed network interface. The issue likely stems from missing or insufficient validation of tunnel endpoints, allowing unauthorized tunnel establishment or traffic injection.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check for loaded IPv6-in-IPv4 tunnel kernel modulesRun `lsmod | grep -E 'sit|ip6tnl|ipv6_tunnel'` to see if tunnel-related kernel modules are loadedAffected if Any of these modules are loaded and the system has network exposure to untrusted sources
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Identify active IPv6-in-IPv4 tunnel interfacesRun `ip -4 tunnel show` and `ip -6 tunnel show` to list all configured tunnel interfacesAffected if Any tunnel interfaces exist and are attached to externally accessible network interfaces
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Check for tunnel endpoint configurations in network setupInspect network configuration files in /etc/sysconfig/network-scripts/ (or equivalent) for TUNNEL or IPV6_TUNNEL settingsAffected if Tunnel configurations exist that bind to interfaces reachable from untrusted networks
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Verify sysctl settings controlling tunnel behaviorCheck `sysctl -a | grep -E 'accept_(ipv6_)?tunnel|forwarding.*6'` for tunnel-related kernel parametersAffected if Tunnel acceptance or forwarding is enabled on interfaces exposed to attackers
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Scan for services listening on tunnel portsUse `netstat -an | grep -E ':41\b|:3544\b|:34555\b'` or `ss -an` to detect listeners on IPv6-in-IPv4 tunnel ports (41, 3544, 34555)Affected if Any service is listening on these tunnel-related ports
The system is affected if IPv6-in-IPv4 tunneling is enabled (modules loaded or tunnels configured) on network interfaces accessible from untrusted or external networks, allowing potential traffic spoofing or injection by remote attackers.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataDisable IPv6-in-IPv4 tunneling on exposed network interfaces unless explicitly required, and implement proper authentication and access controls on tunnel endpoints.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-23019 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-23019 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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